The finite orthogonal group obtained by quotienting a crystal space group by its translation subgroup. In three dimensions there are 32 crystallographic point-group types, constrained by preservation of a lattice. It describes macroscopic rotational and reflection symmetry, not the fractional translations of the full space group.
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A crystallographic point group is a mathematical classification of the symmetry of a crystal structure. These groups describe the symmetry operations that leave at least one point (typically the origin) invariant, meaning those operations do not alter the position of that point. The main symmetry operations included in crystallographic point groups are: 1. **Rotation**: Turning the crystal around an axis. 2. **Reflection**: Flipping the crystal across a plane.